Clinical and laboratory investigative activities are being performed in collaboration with the Pediatric Oncology Study Group (POG). We are participating in cooperative cancer therapy trials which utilize a combination of surgery and/or radiation therapy and/or chemotherapy for the investigative clinical trials of leukemias, lymphomas, and a variety of childhood solid tumors. Summaries of current results of these trials are in some cases already published, and a compilation of pertinent publications from these cooperative group efforts can be obtained from the Pediatric Oncology Group office. We are also participating in several pilot studies of new drug treatment programs and Phase II trials. The University of Alabama in Birmingham (UAB) is currently providing reference laboratory support for performing immunologic evaluation of all new pediatric patients with lymphoblastic leukemia. We perform pre-B cell analysis to determine the immunologic phenotype of a group of formerly unclassified non-B, non-T leukemias. Additionally, T-cell immunologic subset evaluations are performed on all available POG patients with E rosette positive leukemias or lymphomas using monoclonal antibodies directed against T-cell differentiation antigens. These studies should allow better characterization and classification of lymphoid malignancies in childhood. UAB investigators also provide an immunogenetics reference laboratory to evaluate HLA and DR phenotypes on black patients with lymphoblastic leukemia and on a group of white patients with neuroblastoma. Bf typing is perofrmed on material from all new patients with ALL. We are examining the ability of this typing to predict risk for, or resistance to, malignancy. We are also looking for relationships of specific phenotypes to survival once malignancy is established. A third POG reference laboratory examines the incidence of circulating immune complexes in neuroblastoma, lymphoblastic leukemia, and osteosarcoma and their correlation with disease activity. Finally, a POG serum/plasma bank has been established at UAB for maintaining frozen material obtained from all patients with malignant diseases for research purposes.